1 //===-- BlockPointer.cpp --------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "BlockPointer.h"
10
11 #include "Plugins/ExpressionParser/Clang/ClangASTImporter.h"
12 #include "Plugins/ExpressionParser/Clang/ClangPersistentVariables.h"
13 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
14 #include "lldb/Core/ValueObject.h"
15 #include "lldb/DataFormatters/FormattersHelpers.h"
16 #include "lldb/Symbol/CompilerType.h"
17 #include "lldb/Symbol/TypeSystem.h"
18 #include "lldb/Target/Target.h"
19 #include "lldb/Utility/LLDBAssert.h"
20 #include "lldb/Utility/Log.h"
21
22 using namespace lldb;
23 using namespace lldb_private;
24 using namespace lldb_private::formatters;
25
26 namespace lldb_private {
27 namespace formatters {
28
29 class BlockPointerSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
30 public:
BlockPointerSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)31 BlockPointerSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
32 : SyntheticChildrenFrontEnd(*valobj_sp), m_block_struct_type() {
33 CompilerType block_pointer_type(m_backend.GetCompilerType());
34 CompilerType function_pointer_type;
35 block_pointer_type.IsBlockPointerType(&function_pointer_type);
36
37 TargetSP target_sp(m_backend.GetTargetSP());
38
39 if (!target_sp) {
40 return;
41 }
42
43 auto type_system_or_err = target_sp->GetScratchTypeSystemForLanguage(
44 lldb::eLanguageTypeC_plus_plus);
45 if (auto err = type_system_or_err.takeError()) {
46 LLDB_LOG_ERROR(
47 lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DATAFORMATTERS),
48 std::move(err), "Failed to get scratch TypeSystemClang");
49 return;
50 }
51
52 TypeSystemClang *clang_ast_context =
53 llvm::cast<TypeSystemClang>(block_pointer_type.GetTypeSystem());
54
55 std::shared_ptr<ClangASTImporter> clang_ast_importer;
56 auto *state = target_sp->GetPersistentExpressionStateForLanguage(
57 lldb::eLanguageTypeC_plus_plus);
58 if (state) {
59 auto *persistent_vars = llvm::cast<ClangPersistentVariables>(state);
60 clang_ast_importer = persistent_vars->GetClangASTImporter();
61 }
62
63 if (!clang_ast_importer) {
64 return;
65 }
66
67 const char *const isa_name("__isa");
68 const CompilerType isa_type =
69 clang_ast_context->GetBasicType(lldb::eBasicTypeObjCClass);
70 const char *const flags_name("__flags");
71 const CompilerType flags_type =
72 clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
73 const char *const reserved_name("__reserved");
74 const CompilerType reserved_type =
75 clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
76 const char *const FuncPtr_name("__FuncPtr");
77
78 m_block_struct_type = clang_ast_context->CreateStructForIdentifier(
79 ConstString(), {{isa_name, isa_type},
80 {flags_name, flags_type},
81 {reserved_name, reserved_type},
82 {FuncPtr_name, function_pointer_type}});
83 }
84
85 ~BlockPointerSyntheticFrontEnd() override = default;
86
CalculateNumChildren()87 size_t CalculateNumChildren() override {
88 const bool omit_empty_base_classes = false;
89 return m_block_struct_type.GetNumChildren(omit_empty_base_classes, nullptr);
90 }
91
GetChildAtIndex(size_t idx)92 lldb::ValueObjectSP GetChildAtIndex(size_t idx) override {
93 if (!m_block_struct_type.IsValid()) {
94 return lldb::ValueObjectSP();
95 }
96
97 if (idx >= CalculateNumChildren()) {
98 return lldb::ValueObjectSP();
99 }
100
101 const bool thread_and_frame_only_if_stopped = true;
102 ExecutionContext exe_ctx = m_backend.GetExecutionContextRef().Lock(
103 thread_and_frame_only_if_stopped);
104 const bool transparent_pointers = false;
105 const bool omit_empty_base_classes = false;
106 const bool ignore_array_bounds = false;
107 ValueObject *value_object = nullptr;
108
109 std::string child_name;
110 uint32_t child_byte_size = 0;
111 int32_t child_byte_offset = 0;
112 uint32_t child_bitfield_bit_size = 0;
113 uint32_t child_bitfield_bit_offset = 0;
114 bool child_is_base_class = false;
115 bool child_is_deref_of_parent = false;
116 uint64_t language_flags = 0;
117
118 const CompilerType child_type =
119 m_block_struct_type.GetChildCompilerTypeAtIndex(
120 &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
121 ignore_array_bounds, child_name, child_byte_size, child_byte_offset,
122 child_bitfield_bit_size, child_bitfield_bit_offset,
123 child_is_base_class, child_is_deref_of_parent, value_object,
124 language_flags);
125
126 ValueObjectSP struct_pointer_sp =
127 m_backend.Cast(m_block_struct_type.GetPointerType());
128
129 if (!struct_pointer_sp) {
130 return lldb::ValueObjectSP();
131 }
132
133 Status err;
134 ValueObjectSP struct_sp = struct_pointer_sp->Dereference(err);
135
136 if (!struct_sp || !err.Success()) {
137 return lldb::ValueObjectSP();
138 }
139
140 ValueObjectSP child_sp(struct_sp->GetSyntheticChildAtOffset(
141 child_byte_offset, child_type, true,
142 ConstString(child_name.c_str(), child_name.size())));
143
144 return child_sp;
145 }
146
147 // return true if this object is now safe to use forever without ever
148 // updating again; the typical (and tested) answer here is 'false'
Update()149 bool Update() override { return false; }
150
151 // maybe return false if the block pointer is, say, null
MightHaveChildren()152 bool MightHaveChildren() override { return true; }
153
GetIndexOfChildWithName(ConstString name)154 size_t GetIndexOfChildWithName(ConstString name) override {
155 if (!m_block_struct_type.IsValid())
156 return UINT32_MAX;
157
158 const bool omit_empty_base_classes = false;
159 return m_block_struct_type.GetIndexOfChildWithName(name.AsCString(),
160 omit_empty_base_classes);
161 }
162
163 private:
164 CompilerType m_block_struct_type;
165 };
166
167 } // namespace formatters
168 } // namespace lldb_private
169
BlockPointerSummaryProvider(ValueObject & valobj,Stream & s,const TypeSummaryOptions &)170 bool lldb_private::formatters::BlockPointerSummaryProvider(
171 ValueObject &valobj, Stream &s, const TypeSummaryOptions &) {
172 lldb_private::SyntheticChildrenFrontEnd *synthetic_children =
173 BlockPointerSyntheticFrontEndCreator(nullptr, valobj.GetSP());
174 if (!synthetic_children) {
175 return false;
176 }
177
178 synthetic_children->Update();
179
180 static const ConstString s_FuncPtr_name("__FuncPtr");
181
182 lldb::ValueObjectSP child_sp = synthetic_children->GetChildAtIndex(
183 synthetic_children->GetIndexOfChildWithName(s_FuncPtr_name));
184
185 if (!child_sp) {
186 return false;
187 }
188
189 lldb::ValueObjectSP qualified_child_representation_sp =
190 child_sp->GetQualifiedRepresentationIfAvailable(
191 lldb::eDynamicDontRunTarget, true);
192
193 const char *child_value =
194 qualified_child_representation_sp->GetValueAsCString();
195
196 s.Printf("%s", child_value);
197
198 return true;
199 }
200
201 lldb_private::SyntheticChildrenFrontEnd *
BlockPointerSyntheticFrontEndCreator(CXXSyntheticChildren *,lldb::ValueObjectSP valobj_sp)202 lldb_private::formatters::BlockPointerSyntheticFrontEndCreator(
203 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
204 if (!valobj_sp)
205 return nullptr;
206 return new BlockPointerSyntheticFrontEnd(valobj_sp);
207 }
208